A variety of devices exist that move automatically over surfaces of swimming pools to be cleaned. One such pool cleaner operates in cooperation with the reduced pressure caused by a pump to induce debris-laden fluid within a pool to flow through the cleaner (and other filtration equipment if desired). The cleaner functions by causing a valve, or diaphragm, to oscillate, periodically interrupting the fluid flow through the cleaner. This periodic interruption in turn causes movement of the device over the surface to be cleaned. Exemplary cleaners of this type are disclosed in U.S. Pat. Nos. 4,642,833 and 4,742,593, which patents are incorporated herein in their entireties by this reference.
U.S. Pat. No. 5,014,382 ("the Kallenbach patent"), also incorporated herein in its entirety by reference, discloses another fluid-interruption version of an automatic swimming pool cleaner. Illustrated in the Kallenbach patent as being attached to the cleaner are a bumper and a retainer that includes a weight. The retainer, which is integrally formed with a portion of the body of the cleaner, thereby fixes the position of the weight relative to the body. Moreover, rigid plastic is used to form the bumpers of commercially-available cleaners made according to the Kallenbach patent. As noted in the Kallenbach patent (col. 3, line 65 through col. 4, line 3), the bumper, when it contacts an obstruction, assists in lifting the flexible disc of a cleaner
from the surface and thus breaking the pressure holding the disc . . . to the surface being traversed. This allows the cleaner . . . to move freely until it disengages from the obstruction.